The restoration of a failed system component's share of a load to a replacement component after a failback event.

When a failed controller in a redundantconfiguration is replaced, the devices that were originally controlled by the failed controller are usually failed back to the replacement controller to restore the I/O balance, and to restore failure tolerance. Similarly, when a defective fan or power supply is replaced, its load, previously borne by a redundant component can be failed back to the replacement part.

A mode of operation for failure tolerant systems in which a component has failed and its function has been assumed by a redundant component.

A system that protects against single failures operating in failed over mode is not failure tolerant, since failure of the redundant component may render the system unable to function. Some systems (e.g., clusters) are able to tolerate more than one failure; these remain failure tolerant until no redundant component is available to protect against further failures.

The automatic substitution of a functionally equivalent system component for a failed one.

The term failover is most often applied to intelligent controllers connected to the same storage devices and host computers. If one of the controllers fails, failover occurs, and the survivor takes over its I/O load.

The ability of a system to continue to perform its function (possibly at a reduced performance level) when one or more of its components has failed.

Failure tolerance in disk subsystems is often achieved by including redundant instances of components whose failure would make the system inoperable, coupled with facilities that allow the redundant components to assume the function of failed ones.

A technique for reducing the time required to synchronize a split mirror with the set of storage devices from which it was split.

Fast mirror resynchronization requires that a list of changes to the original set of data since moment of splitting be kept. When the split mirror is rejoined to the original set of volumes, only the data items identified in the list are copied from the original to the split mirror rather than the entire contents of the devices.

In this and other FC-related entries, the numbers denote versions of the spec, developed and maintained by the INCITS T11 committee, that bears that name. The listed version is current as of this writing.

A Fibre Channel Switching Device with one or more Lossless Ethernet MACs, each coupled with an FCoE Controller, and optionally one or more Lossless Ethernet bridging devices and optionally an FC Fabric interface.

An FCF forwards FCoE frames addressed to one of its FCF-MACs based on the D_ID of the encapsulated FC frames.

Both FDDI-fiber adapters that connect to optical fiber FDDI networks, and FDDI-TP adapters that connect to twisted copper pair FDDI networks exist. Although network interface cards are usually referred to as NICs rather than as adapters, the term FDDI adapter is more common than FDDI NIC. See NIC.

FibreChannel supports point to point, arbitrated loop, and switched topologies with a variety of copper and optical links running at speeds from 1 Gb/s to 10 Gb/s. The committee standardizing Fibre Channel is the INCITS Fibre Channel (T11) Technical Committee.

Nodes connected to a Fibre Channel Arbitrated Loop arbitrate for the single transmission that can occur on the loop at any instant using a Fibre Channel Arbitrated Loop protocol that is different from Fibre Channel switched and point to point protocols. An arbitrated loop may be private (no fabric connection) or public (attached to a fabric by an FL_Port). The network is defined by the FC-AL-2 standard INCITS 332 - 1999 [R2004].

A mutual benefit corporation formed under the non-profit corporation laws of the State of California, whose members consist of companies that manufacture Fibre Channel systems, components, software, and tools, as well as provide Fibre Channel education and services to end-user customers.

A technical report specifying common methodologies for both arbitrated loop and switched environments, with the intention of facilitating interoperability between devices whether they are connected in a loop or Fabric topology.

An ANSI standard that describes the protocols used to implement security in a Fibre Channel fabric.

This standard includes the definition of protocols to authenticate Fibre Channel entities, protocols to set up session keys, protocols to negotiate the parameters required to ensure frame-by-frame integrity and confidentiality, and protocols to establish and distribute policies across a Fibre Channel fabric.

An abstract data object made up of (a.) an ordered sequence of data bytes stored on a disk or tape, (b.) a symbolic name by which the object can be uniquely identified, and (c.) a set of properties, such as ownership and access permissions that allow the object to be managed by a file system or backup manager.

Unlike the permanent address spaces of storage media, files may be created and deleted, and in most file systems, may expand or contract in size during their lifetimes.

A namespace-based network-oriented infrastructure for files that includes a decoupling layer that separates logical file access from physical file location, and enables a variety of services (e.g., replication and migration) to be applied to files and file systems.

A software component that imposes structure on the address space of one or more physical or virtual disks so that applications may deal more conveniently with abstract named data objects of variable size (files).

File systems are often supplied as operating system components, but are also implemented and marketed as independent software components.

Spelling filesystem as a single word is also correct, especially when the term is used as an adjective.

An FL-Port becomes a shared entry point for public NL-Port devices to a Fibre Channel fabric. FL-Ports are intermediate ports in virtual point-to-point links between end ports that do not reside on the same loop, for example the NL-Port on an end node to the FL-Port on a switch to the F-Port in that switch to the N_Port on that end node through a single Fibre Channel fabric switch.

An accurate bit-for-bit reproduction of the information contained on an electronic device or associated media, whose validity and integrity has been verified using an accepted algorithm. [NIST SP 800-72]

The preparation of a disk for use by writing required information on the media.

Disk controllers format disks by writing block header and trailer information for every block on the disk. Host software components such as volume managers and file systems format disks by writing the initial structural information required for the volume or file system to be populated with data and managed.

In a simple world, free space is normally the same as assigned capacity less the amount of assigned capacity already written. But restrictions such as quotas and interactions between systems using different arithmetic may cause the reported free space to vary from the actual quantity.

The average rate at which a single disk transfers a large amount of data (e.g., more than one cylinder) in response to one I/O request.

The full-volume data transfer rate accounts for any delays (e.g., due to inter-sector gaps, inter-track switching time and seeks between adjacent cylinders) that may occur during the course of a large data transfer. Full volume transfer rate may differ depending on whether data is being read or written. If this is true, it is appropriate to speak of full-volume read rate or full-volume write rate. Also known as spiral data transfer rate.

F_Ports are intermediate ports in virtual point-to-point links between end system ports, for example the N_Port on an end node to the F_Port on a switch to the F_Port in that switch to the N_Port on the other end node using a single Fibre Channel fabric switch. An F_Port is assumed to always refer to a port to which non-loop PN_Ports are attached to a Fabric, and does not include FL_Ports [FC-FS-2].